The present invention relates to a seat cushion airbag apparatus that is configured to inflate an airbag installed in a seat portion of a vehicle seat, such as an automobile seat, with inflation gas, to raise the seating face, thereby restraining an object-to-be-restrained, such as an occupant, on the seat portion, from moving forward.
When an impact due to a frontal collision is applied to an automobile from front, the lumbar region of the occupant restrained to an automobile seat by the seat belt device may be disengaged from the lap belt portion and move forward. A number of countermeasures against this phenomenon have been implemented or proposed.
For example, Japanese Laid-Open Patent Publication No. 2009-132245 discloses a seat cushion airbag apparatus that is employed in an automobile seat having a cushion portion. The cushion portion is supported from below by a support portion of the seat frame.
As shown in FIG. 15, the seat cushion airbag apparatus includes at least an airbag 101 and an elongated gas generator 107. The airbag 101 is arranged between the support portion and the cushion portion. The outer shape of the airbag 101 is formed by an airbag main body 102. The airbag main body 102 has an insertion opening 103 at the front end. The insertion opening 103 extends in the width direction of the automobile seat (automobile width direction) and is shorter than the gas generator 107 in the width direction. The airbag main body 102 also includes a lower fabric portion 104, which configures the lower part. The lower fabric portion 104 has several insertion holes at the front end. These insertion holes are located at positions spaced apart in the width direction of the automobile seat and include a specified insertion hole 105, which is farthest from a harness 108, and remaining general insertion holes 106. The harness 108 will be discussed below.
The gas generator 107 is arranged at the front end in the airbag main body 102 and in a position to extend in the automobile width direction. The harness 108 is connected to a first end of the gas generator 107. The gas generator 107 has several bolts extending downward from positions spaced apart in the longitudinal direction. The bolts include a specified bolt 109, which is farthest from the harness 108, and remaining general bolts 110.
The specified bolt 109 is inserted into the specified insertion hole 105 and is fastened to the support portion of the seat frame. Each general bolt 110 is inserted into the corresponding general insertion hole 106 and fastened to the support portion. The harness 108 is drawn out of the airbag main body 102 through the insertion opening 103.
The seat cushion airbag apparatus is configured as described above.
Thus, when an impact is applied to the automobile from the front with respect to the automobile seat, for example, due to a frontal collision, the occupant acts to move forward due to inertia. The restraining action of the seat belt device holds the occupant on the seat portion. However, depending on the posture of the occupant, the lumbar region may act to move forward.
The gas generator 107 of the seat cushion airbag apparatus discharges inflation gas in response to the frontal impact to inflate the airbag main body 102. Accordingly, the cushion portion is pushed upward so that the seat surface of the seat portion bulges. In the thighs of the occupant, who is restrained onto the automobile seat by the seat belt device, regions close to the backs of the knees are pushed upward, so that the lumbar region is pushed against the lap belt portion. This improves the performance of the lap belt portion to restrain the occupant, thereby restricting the forward movement of the lumbar region.
In the above described seat cushion airbag apparatus, when the gas generator 107 is installed in the airbag main body 102, a second end of the gas generator 107, to which the harness 108 is not connected, is first inserted through the insertion opening 103 into the front end of the airbag main body 102. As shown in FIG. 15, the specified bolt 109 is inserted into the specified through hole 105.
Subsequently, the gas generator 107 is rotated toward the insertion opening 103 about the specified bolt 109. The rotation causes the gas generator 107 to enter the front end in the airbag main body 102 through the insertion opening 103. The harness 108, which is connected to the gas generator 107, is drawn out of the airbag main body 102 through the insertion opening 103.
When the general bolts 110 are aligned with the general insertion holes 106 as indicated by the long dashed double-short dashed line in FIG. 15, the general bolts 110 are inserted into the general insertion holes 106. Thus, the gas generator 107 is secured to the airbag main body 102 with its position determined with respect to the airbag main body 102.
After being respectively inserted into the specified insertion hole 105 and general insertion holes 106, the specified bolt 109 and the general bolts 110 protrude out from the airbag main body 102. The specified bolt 109 and the general bolts 110 are fastened to the seat portion at the protruding portions.
However, in the above described conventional seat cushion airbag apparatus, if a long gas generator 107 is used, the gas generator 107 may catch on the end of the insertion opening 103 closer to the harness 108 during rotation of the gas generator 107 about the specified bolt 109, which is inserted into the specified hole 105. In this case, it is difficult to insert the gas generator 107 into the front end in the airbag main body 102 through the insertion opening 103.